Agricultural combines are heavy large machines that harvest, thresh, separate and clean harvested crop, planted agriculturally that carries corn. They include steerable rear wheels mounted on the free ends of rear axles that pivot about a central longitudinal axis.
The axles are telescopic and can be varied in length by stopping the vehicle, loosening clamps and forcing the extendible axle member in (or out) of an outer axle member until a desired axle length is achieved, then tightening short axle clamps to lock the extensible axle member and the outer axle member in that position.
In new harvesters, it has been proposed to permit the extendible axle of the combine to slide in and out of the outer axle while the vehicle is being driven through a field. Hydraulic actuators have been considered for use to extend the axles during operation. In this arrangement the extendible axle member and outer axle member may be provided with a releasable clamp that can be opened when the axles are telescoped and then reapplied when the axle has the desired length.
Axles that can be extended and retracted while the agricultural combine is under way performing its harvesting functions will require improved axles with tighter tolerances and greater load capacity than existing agricultural combine axles.
U.S. Pat. No. 5,121,808 shows a telescoping steering axle with a non driven (gauge) wheel supported on an inner axle member. The inner axle slides loosely into the outer axle and is clamped against one side of the outer axle by bolts that pass through the inner and outer axle. The bolts are located at the outer end of the outer tube and the inner tube is unsupported. This arrangement of telescoped axles that are unclamped while the vehicle is stationary, extended while stationary, then clamped for operation while stationary will not permit the clamped axle to be moved during operation as the agricultural combine travels through the field.
U.S. Pat. No. 5,464,243 shows an extendible axle for a self-propelled sprayer having an outer axle and an inner axle. A clamping arrangement in the form of a V-shaped wedge with plastic shims on top is provided at the bottom of the outer end of the outer tube. Bolts in the bottom of the outer tube are provided to abut the wedge and force it up against the inner tube, lifting the inner tube and wedging in against a plastic shim at the top of the outer tube. This permits the axle, as it wears to be adjusted to remove slack. The bolts are tightened to lock the inner tube in position with the new preferred row spacing. This arrangement is used for relatively lightweight vehicles such as sprayers. The loads are transferred directly to short threads in the wall of the outer axle tube. A vehicle experiencing high loads, (such as an agricultural harvester) runs the risk of tearing these short threads out.